Access control systems restrict entrance to a building, or individual rooms within that building, to authorized personnel. For example, an access control system determines who is allowed to enter or exit a premises based on a wide range of authentication credentials. Conventionally, access control systems decisions are made by comparing a user credential received through a keypad or card reader to an access control list existing within a server at a remote location, via a network. However this poses a problem in instances where a network may be unavailable, for example if the network is down, or alternatively, if a building does not have network connectivity at all.